The need to have cosmetically acceptable, sprayable, low or zero ethanol fragrance formulations is due to concerns about volatile organic compounds (VOC), which are claimed to produce ground level ozone under certain extreme weather conditions. Fragrances at levels of 0.5% or above are most commonly solubilized with ethanol. However, ethanol is considered to be a VOC under many current and pending regulations.
The task of producing a low or zero ethanol formulation, which resembles an ethanolic fragrance formulation in all aspects, is difficult and the problem increases as the level of fragrance increases. Low ethanol formulations are formulations which are substantially free of ethanol.
Blakeway (Perfumer & Flavorist, 18, Jan/Feb., p. 23, 1993) reviews water based perfumes. He focuses on the use of solubilizers, in particular, non-ionic surface active agents. The formulations given by Blakeway require high ratios of surfactant to perfume oil which leave a sticky feeling on the skin and can produce unwanted levels of product foaming. At page 24, column 1, paragraph 3 Blakeway indicates that perfume compositions having 10% or greater perfume oils give viscosities of 20-50 cps which can not be used in conventional pump sprays. Also, higher concentrations of surfactants needed for the higher concentration of perfume oils gives the microemulsions their tendency to foam in the bottle. At page 26 under the heading "pump spray" this document teaches that a viscosity of less than about 15 cps (at 20.degree. C.) of a water based perfume is needed for pump spray applications.
Microemulsions represent one approach to producing clear, transparent products. These are dispersions of oil-in-water or water-in-oil systems in which the droplet size is small enough to permit light to pass through. U.S. Pat. No. 4,146,499 shows how oil-in-water microemulsions can be prepared using a primary surfactant with a hydrophilic-lipophilic balance ("HLB") not substantially less than required to make it soluble in the oil phase. A second surfactant having a higher HLB than the primary surfactant, is used to convert the dispersion to a microemulsion. Non-ethanol fragrances produced by this method are viscous and translucent even at low, e.g., 1%, fragrance levels.
Linn et al., discloses in U.S. Pat. No. 4,797,272, water-in-oil microemulsions for cosmetic uses containing moisturizing agents or sunscreens. These microemulsions are formulated with non-ionic surfactants and produce products comparable to typical skin care creams and lotions and are not at all similar to perfume and cologne formulations. While some may be flowable, none is sprayable and non-tacky which are fundamental requirements for replacement of ethanolic perfume products.
U.S. Pat. No. 5,252,555 to Dartnell et al relates to microemulsions containing a perfuming concentrate from 5 to 50% by weight, and a surfactant based on polyethylene glycol, a first co-surfactant based on polyglycerol and a second co-surfactant based on ether phosphate. Thus the compositions contain a very large amount of surfactant. Moreover, the surfactants utilized in these compositions are non-ionic surfactants.
European Patent 516508 corresponds to U.S. Pat. No. 5,252,555 to Dartnell. The U.S. patent English version is discussed above.
Microemulsions in which the primary surfactant is anionic have been studied. However, coactives are required to modify the HLB and allow the formation of microemulsions. This prior art (as discussed by Friberg, et al, Cosmetics & Toiletries, Vol. 97, June 1982 and Kozo Shinoda and Hironobu Kunieda in Microemulsions, Theory and Practice, ed., Leon Prince, Academic Press, 1977) disclosed that a lipophilic coactive, such as a medium chain length alcohol, is required to reduce the HLB into the range required for microemulsion formation. Use of these lipophilic coactives as the sole coactive at the required levels for microemulsions, is not desirable for perfume compositions because they typically have unpleasant odors and frequently have undesirable skin feel characteristics.
U.S. Pat. No. 4,146,499 to Rosano teaches the use of two surfactants to produce microemulsions, but does not produce sprayable compositions at higher perfume oil concentrations. The non-ethanol fragrances produced by this method are viscous and translucent even at low, for example 1%, fragrance levels. The language in this patent is very broad as regards a first surfactant which is lipophilic and a second surfactant which is hydrophilic.
European Patent 571,677 relates to clear oil-in-water microemulsions comprising a perfume oil, an aqueous phase and a surfactant. The microemulsions comprise less than 25%, preferably less than 5% alcohol. The surfactants may be either ionic or non-ionic. The co-surfactants are present in less than 50% by weight of the total surfactant as described on page 5, lines 33-38. This patent does not describe an anionic surfactant at a concentration lower than a coactive. Further, the European patent application does not describe any microemulsions comprising a perfume oil, an anionic surfactant in combination with a hydrophilic coactive solvent, wherein the hydrophilic coactive is in higher concentration than the anionic surfactant.
European Patent 572,080 to Behan et al concerns aqueous perfume oil micro-emulsions. The text of the patent application is similar to the text of European Patent 571,677. Example 3 shows a combination of primary nonionic surfactants plus cosurfactants at least one of the cosurfactants being anionic. The micro-emulsions are characterized as being fine fragrances or air fresheners. The claim states that the weight ratio of perfume oil to total surfactant is between 0.85 and 2.5, which stated in the reverse is that the ratio of total surfactant to perfume oil is from about 0.4 to about 1.2.
Other background art is discussed below.
Japanese Kokai 161698/1993 to ST Chemicals Limited relates to water soluble solvents and water in combination with perfume oils. Accordingly this document does not relate to perfume oils micro-emulsified via an anionic surfactant in combination with a hydrophilic coactive.
U.S. Pat. No. 5,283,056 to Chung et al relates to mouthwash compositions comprising water, a flavor or fragrance oil, and one or more surfactants. As described on page 4, lines 50-55 the mouthwash compositions have a viscosity ranging from about 70 to about 18,000 cps.
Japanese Patent 57-159707 relates to solubilizing perfume oils in water or an aqueous medium. A mono- or poly-hydric alcohol is used in combination with a surfactant to solublize the perfume oils.
U.S. Pat. No. 4,089,814 to Schmolka relates to roll-on perfume compositions comprising 25-40 parts of an alcohol and block copolymers as well as water. A requirement for such compositions is that the compositions are viscous, clear and stable perfumes. Clearly such viscous compositions are not sprayable compositions. Further there is no mention of an anionic surfactant in combination with a hydrophilic coactive.
EP 261,351 to Blakeway relates to aqueous or aqueous-alcoholic solutions of fat soluble perfume oil containing an alkylene oxide polymer and a nonionic emulsifier. Thus document does not describe sprayable perfumes utilizing an anionic surfactant in combination with a hydrophilic coactive.
U.S. Pat. No. 4,268,498 to Gedeon et al relates to solid clear cosmetic sticks. Thus, sprayable compositions are not described. Although the compositions are described as clear they are also viscous because they are in a solid stick form.
German Patent 2901068 relates to deodorant compositions. The composition is a clear solution comprising a large amount of an anionic surfactant.
German Patent 3304822 relates to an odorant composition containing hexaalkyl-cyclo-trisiloxane perfume vehicles which dissolve a perfume and sublimate into the environment carrying the perfume into the air. Other volatile additives can be included to reduce the sublimation rate. Therefore, this document does not disclose a combination of an anionic surfactant and a coactive. The carrier agent is non-ionic.
U.S. Pat. No. 5,079,227 to Handjani et al relates to perfume compositions, with an aqueous phase, having a high concentration of perfume contained within nonionic lipid "vesicles." The lipid vesicles are derived from a linear or branched polyglycerol. Such lipid vesicle compositions are distinguished from oil-in-water or water-in-oil emulsions by Handjani et al in their discussion of background art. Further, the examples on pages 4-6 of Handjani et al refer to the compositions as compositions having the appearance of a cream.
U.S. Pat. No. 4,810,690 to Dumas relates to non-flammable homogeneous liquid air freshener compositions with an organic solvent base, which are not microemulsions of perfume oils.
UK Patent 2,230,447 relates to solublized air freshener compositions, rather than to microemulsified perfume compositions. A primary alcohol is used to solubilize the perfume oil in the described compositions. A secondary low volatility solvent, such as a glycol ether is used to slow the evaporation of the alcohol solvent. Thus the mechanism is not the formation of a clear microemulsion, but rather a homogeneous solution is formed.